Power tong positioning apparatus

ABSTRACT

Well pipe positioning apparatus having a vertically disposed column formed of a central web joined between two parallel flanges and provided with bearing units adapted to be mounted in a well derrick to permit vertical and horizontal support for the column while permitting the column to pivot horizontally. A vertically movable rectangular hollow support collar is fitted about the column and supported in alignment for movement up and down the column by roller means rigidly mounted within the collar and mounted in rolling contact with the inside faces of the column flanges. A pipe tong support yoke structure is rigidly mounted at a first end to the support collar to extend horizontally and radially from the pivotable column. The yoke structure is adapted to receive and support a power tong assembly including a pipe back-up unit disposed in parallel relation to a pipe rotating unit through a supporting cradle means mounted to the second end of the yoke structure. The cradle means provides firm vertical support of the back-up unit in parallel relation to the yoke structure and provides support with limited vertical and radial movement of the rotating unit with respect to the back-up unit and to the support yoke. A power source providing linear movement is mounted in upright position adjacent the column with its lower end mounted to the lower support member and its upper end connected through a flexible force transfer means to the support yoke, the flexible force transfer means being anchored relatively between the yoke structure and the lower support member and being connected across a force transfer crosshead means mounted to the upper end of the power source.

United States Patent 191 Barron et a1.

[11] 3,780,815 Dec. 25, 19 73 1 POWER TONG POSITIONING APPARATUS [75] Inventors: Charles Dwain Barron, Huntington;

Bela Geczy, Glendale; Carl Alfred Wilms, La Habra, all of Calif.

[73] Assignee: Byron Jackson, lnc., Long Beach,

Calif.

22 Filed: Jan. 7, 1972 21 Appl. No.: 216,216

[52] US. Cl 173/43, 81/57.16, 81/5735,

I 166/77.5 [51] Int. Cl. E211) 19/16 [58] Field of Search 166/77.5, 78, 85;

[56] References Cited Primary ExaminerWerner H. Schroeder Attorney-William S. McCurry et al.

[5 7] ABSTRACT Well pipe positioning apparatus having a vertically disposed column formed of a central web joined between two parallel flanges and provided with bearing units adapted to be mounted in a well derrick to permit vertical and horizontal support for the column while permitting the column to pivot horizontally. A vertically movable rectangular hollow support collar is fitted about the column and supported in alignment for movement up and down the column by roller means rigidly mounted within the collar and mounted in rolling contact with the inside faces of the column flanges. A pipe tong support yoke structure is rigidly mounted at a first end to the support collar to extend horizontally and radially from the pivotable column, The yoke structure is adapted to receive and support a power tong assembly including a pipe back-up unit disposed in parallel relation to a pipe rotating unit through a supporting cradle means mounted to the second end of the yoke structure. The cradle means provides firm vertical support of the back-up unit in parallel relation to the yoke structure and provides support with limited vertical and radial movement of the rotating unit with respect to the back-up unit and to the support yoke. A power source providing linear movement is mounted in upright position adjacent the column with its lower end mounted to the lower support member and its upper end connected through a flexible force transfer means to the support yoke, the flexible force transfer means being anchored relatively between the yoke structure and the lower support member and being connected across a force transfer crosshead means mounted to the upper end of the power source.

13 Claims, 11 Drawing Figures PAIENIEU ntcz 5 I915 sum 1 or 4 PATENTEB [E82 5 I925 .SNEEIZDF I N Gum PATENTED "3325 I973 3. 780.8 1 5 saw n 0r 4 FIG: 8. FIG. 9.

1 POWER TONG POSITIONING APPARATUS BACKGROUND OF THE INVENTION This invention generally pertains to apparatus for positioning well pipe power tongs as are utilized to connect and disconnect sections of threaded pipe during the insertion of a string of such pipe in a well bore and the removal of such pipe string from the well bore.

The invention more specifically pertains to improved apparatus for supporting and positioning the larger and heavier power tongs currently being utilized for the heavier strings of pipe necessary for present day deep wells. Such power tongs are disclosed, for example, in the applications of Bela Geczy et al., filed Apr. 16, 1971, Ser. No. 134,554, for Chain Driven Spinning Make Up and Break Out Tongs, now U.S. Pat. No. 3,691,875, issued Sept. 19, 1972; Carl A. Wilms, filed Apr. 16, 1971, Ser. No. 134,553, for Chain Actuated Pipe Tongs; and Carl A. Wilms, filed Apr. 16, 1971, Ser. No. 134,552, for Combined Back Up Tong and Power Tong with Joint Motion Compensation now abandoned in favor of continuation application Ser. No. 216,182, filed Jan. 7, 1972. The disclosures of these identified applications are specifically incorporated herein by reference.

Various apparatus for positioning and supporting power tongs and the like has been previously developed as shown in U.S. Pat. Nos. 3,288,000, 2,668,689, 2,567,039, 2,518,398, 2,474,336 and 2,450,934, for example.

SUMMARY OF THE INVENTION This invention provides positioning apparatus particularly suited to supporting and positioning large and heavy power tongs.

The invention also provides positioning apparatus capable of convenient manipulation and closely controlled vertical placement of power tongs.

The apparatus of the invention further provides controlled support of such power tongs during connection and disconnection of pipe.

The foregoing and other provisions and advantages are attained in a pipe tong positioning apparatus having a vertically disposed column formed of a central web joined between two parallel flanges and provided with lower and upper support members respectively equipped with a lower bearing unit adapted to be mounted to a fixed support in a well derrick and an upper bearing unit adapted to be connected through horizontal tie members to the structure of the derrick, such arrangement providing vertical and horizontal support for the column while permitting the column to pivot horizontally. A vertically movable rectangular hollow support collar is fitted about the column and supported in alignment for movement up and down the column by pivoting roller means rigidly mounted within the collar and mounted in rolling contact with the inside faces of the column flanges. A pipe tong support yoke structure is rigidly mounted at a first end to the support collar to extend horizontally and radially from the pivotable support column. The yoke structure is adapted to receive and support a power tong assembly including a back-up unit disposed in parallel relation to a pipe rotating unit through s supporting cradle means mounted to the second end of the yoke structure. The cradle means provides firm vertical support of the back-up unit in parallel relation to the yoke structure and provides support with limited vertical and radial movement of the rotating unit with respect to the backup unit and'to the support yoke. A power source providing linear movement is mounted in upright position adjacent the column with its lower end mounted to the lower support member and its upper end connected through a flexible force transfer means to the support yoke, the flexible force transfer means being anchored relatively between the yoke structure and the lower support member and being connected across a force transfer crosshead means mounted to the upper end of the power source.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevational view of a positioning apparatus of the present invention;

FIG. 2 is a partially sectional plan view taken along the line 2-2 of FIG. 1;

FIG. 3 is a partially sectional elevational view taken along line 3-3 of FIG. 1;

FIG. 4 is a partially cut away plan view taken along line 4-4 of FIG. 1;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 1;

FIG. 6 is a sectional view taken along the line 6-6 of FIG. 4;

FIG. 7 is a sectional view taken along the line 7-7 of FIG. 2;

FIG. 8 is a partially sectional elevational view of the tong cradle assembly shown in FIG. 1 and taken along the line 8--8 of FIG. 1;

FIG. 9 is a partially sectional elevational view of part of the tong cradle assembly shown in FIG. 1 and taken along the line'99 of FIG. 8.

FIG. 10 is a sectional view taken along the line 10-10 of FIG. 9; and

FIG. 11 is a sectional view taken along the line 11-11 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2 there is shown a positioning apparatus of this invention which generally includes a vertically disposed column 10 formed of a web joined between two parallel flanges such as an I-beam, for example. A lower support 14 is joined to the bottom of column 10 as by welding, for example, and an upper support 12 is connected with the top of column 10 as by bolted connection as shown, for example. Upper support 12 is connected to a pivotable upper bearing unit 16, best shown in FIGS. 1, 4 and 6. Lower support 14-is connected to a pivotable lower bearing unit 18, best shown in FIGS. 1, 2 and 7.

A generally hollow and elongated rectangular support collar 20, shown in FIGS. 1, 2 and 3, is fitted about column 10 and adapted to be moved up and down along column 10. Collar 20 is maintained and rigidly supported in longitudinal movable alignment with column 10 by a roller assembly 22 incorporated within collar 20 as shown in FIGS. 1-3. As shown, a plurality of flanged rollers 23 are included in assembly 22 and mounted to abut and roll along the inner faces of the flanges of column 10 with the roller flanges abutting the side edges of the column flanges to maintain collar 20in fixed horizontal or lateral relation with respect to column 10.

A tong support yoke structure 24 is mounted to collar 20 and projects horizontally and radially from the pivotable axis of column 10. A power pipe tong assembly 26 adapted to receive a well pipe 1 and including a back-up tong 28 and a rotating tong 30 is mounted within yoke 24 through a cradle assembly having cradle units 32 and 32. For the purpose of this disclosure, the power tong assembly 26 may be considered to be of construction such as disclosed in the previously referenced U.S. patent disclosure, for example.

Mounted in generally upright posture adjacent colum is a power source adapted for linear movement which is provided as a hydraulic piston and cylinder unit 34. As later described, power source 34 is pivotally mounted at its lower end to lower support 14 and ter minates at its upper movable end with a force and movement crosshead unit 38. Flexible force and movement transfer means are provided as a pair of roller chains 36 and 36 which are respectively meshed across chain sprockets incorporated as part of crosshead unit 38. Chains 36 and 36' are also respectively anchored at their lower ends to lower support member 14 and extend upwardly over crosshead unit 38 to a position below unit 38 where such chains are respectively anchored to yoke structure 24.

As a matter of perspective, the combined weight of the power tong assembly 26 including back-up tong unit 28 and rotating tong unit 30 may be in the order of 15,000 lbs. (68,000 kilograms) and may be able to exert relative torque in the range of 75-l00,000 ft/lbs. (1 l3-l48,800 kilogram/meters), for example. The weight of the tong positioning apparatus supporting the tong assembly may be in the order of 12,500 lbs. (57,700 kilograms), for example, the combined weight of the tong assembly and the positioning apparatus then being about 27,500 lbs. (125,700 kilograms). As further examples, the dimensions of the positioning apparatus may be in the order of a distance of 17 ft. (5.2 meters) from support 14 to the top of bearing unit 16 and a distance of 9.5 ft. (2.9 meters) from the pivoting axis of column 10 to the pipe receiving centers of tong units 28 and 30. Such dimensions will permit power tong assembly 26 to move a vertical distance of asmuch as about 10 ft. (3 meters) as may be required during connection and disconnection of well pipe. Such torque, weights and dimensions are exemplary only and may of course be varied for specific applications of the invention.

It is to be noted that the construction of the positioning apparatus as generally described will provide for linear movement of power source 34' and crosshead unit 38 to cause perpendicular movement. of yoke structure 24 and tong assembly 26 in an amount equal to twice the movement of the crosshead unit. Such construction permits provision of a power source 34 of shorter efiective length with attendant advantages and also provides greater response of yoke structure 24 to a given increment of movement by the power source.

As will also be noted with reference to the drawing and this description, the positioning apparatus of this invention may be of predominantly welded fabrication which incorporates commonly available components such as standard structural steel shapes, bars, plate and the like.

The lower support assembly 14 and the lower bearing unit 18 are best shown in FIGS. 1, 2, 3 and 7. As shown, bearing unit 18 isa flanged ball bearing assembly connected to support 14 and to a fabricated mounting base 40 by means of fasteners such as cap screws 42. Base 40 is mounted on or forms a part of a well derrick floor 44.

FIGS. 2 and 7 show an arcuately slotted retaining lug 46 mounted to and projecting from support 14. Appropriately mounted to base 44 is a retaining socket 48. The slot of lug 46 and the socket 48 are oriented to permit a removable retaining pin 50 to be extended through such slot to be seated in socket 48 when column 10 and yoke 24 are pivoted to a position where the pipe openings of tong assembly 26 are retained in general registry with the well bore extending downwardly beneath the well derrick (not shown). The purpose of the slot in lug 46 is to permit slight arcuate deviation of tong assembly 26 to accommodate slight lateral movement of pipe passing through the tong assembly as such pipe is connected or disconnected.

Upper support member 12 is provided as removable to permit the assembly of support collar 20 as shown in FIGS. 1, 2 and 3. Upper support assembly 12 is removably attached to column 10 through provision of downwardly projecting support flanges 52 which are respectively connected to the flanges of column 10 by'means of bolts 54. Upper bearing unit 16, shown in H68. 1, 3, 4, and 6, is a flanged ball bearing assembly connected to support 12 and to a cylindrical retaining bitt 56 by means of fasteners such as cap screws 58. Bitt 56 is equipped with a plurality of lobed and divided retainer rings such as indicated at 60 and 62. Rings 60 and 62 are assembled with fasteners such as cap screws 61, for example. Horizontal tie bars 64 and 66 are respectively connected to the lobes of rings 60 and 62 through clevis and pin arrangements 68 and 70. The other ends of tie bars 64 and 66 are connected in tension to the structure (not shown) of the well derrick. To be noted is that more than the two disclosed tie bars may be utilized as desired to provide appropriate horizontal stability in a particular installation.

The details of support collar 20 and alignment roller arrangement 22 are shown in FIGS. 1, 2 and 3. Collar 20 is shown to be of welded fabrication and incorporating a front load plate 72, side plates 74 and a rear plate 76 with such plates being reinforced in the rectangular shape as shown by a plurality of stiffening ribs 78. R01- ler support plates 80 are mounted within collar 20 in parallel relation to side plates 74 and supported by support webs 82 as shown. Side plates 74 and support plates 80 are appropriately bored to receive the removable axles of the flanged alignment rollers 23 as shown. As provided, collar 20 has free longitudinal movement along column 10 but is otherwise supported against movement with respect to column 10.

Yoke 24 includes a clevis box 84 mounted at the upper part of load plate 72 and support arms 86 and 86' mounted to and projecting from the lower part of load plate 72. Support cradles 32 and 32' are respectively mounted to arms 86 and 86, as later described with reference to F168. 8, 9 and 10, and secured through pinnedconnection to members 88 and 88' of a support fork 90 to clevis box 84. Clevis box 84 defines a cavity which will receive chain crosshead 38 and is provided with a chain anchor bracket 92 to which chains 36 and 36' are secured by bolted connection as shown (FIGS. 1, 2 and 5). The other lower ends of chains 36 and 36 are secured to cars 94 and 94' by suitable pins or the like as shown in FlGS. 1 and 3.

Power source 34 as provided includes a piston and cylinder unit having a cylinder 96 with a piston rod 98 extending from the cylinder. Chain crosshead 38 is mounted to the distal end of rod 98 and cylinder 96 is pivotally mounted to lower support 14 through a clevis and pin arrangement 100. Cylinder 96 is equipped with a fluid fitting 102 through which fluids under pressure may be forced into or discharged from the cylinder to cause extension and retraction of piston rod 90 with corresponding perpendicular movement of support yoke 24, as previously described. Though compressible fluids such as air may be used, incompressible hydraulic fluids such as oil is preferred in the operation of the invention.

FIGS. 1, 2, 8, 9 and show the supporting cradle including cradle units 32 and 32. Cradle unit 32' is provided of construction which is in mirror image of the construction of cradle unit 32 and accordingly need not be described in detail. FIGS. 8, 9 and 10 best show the details of cradle unit 32. Cradle unit 32 generally includes a supporting guide 104 formed at the extremity of support arm 86 which guides and supports a tong unit carrier frame 106 in pivoting and radially movable relation through a roller unit 108 as shown.

Supporting guide 104 is formed of generally rectangular configuration with a pair of upwardly extending ears which form a clevis 110 for attachment by means of a pin to support fork 90. Parallel trackways 112 are horizontally and radially defined within guide 104 and closed at the distal end of support arm 86 by a closure bar 114 connected across the trackways to guide 104 by fasteners such as cap screws 116 as shown. A flanged guide block 118 is snugly fitted in sliding relation within trackways 1 12 with the flanges of the guide block abutting the sides of the trackways and maintaining the guide block in radial alignment with support arm 86. Adjustable radial support of guide block 118 is provided by a threaded stud 120 projecting from the guide block 118 through a hole in closure bar 1 14 with threaded lock nuts 122 adjustably threaded on stud 120 and tightened to lock on either side of bar 114. A short machined slot 124 having circular ends is horizontally defined in guide block 118 which slot receives roller 108 and permits limited radial movement of the roller within the slot for purposes later described. Roller 108, as disposed within slot 124, is secured by means of a pin to a clevis 126 formed as an upper part of carrier frame 106 in a manner as shown to cause carrier frame 106 to be suspended in pivoted and radially movable relation through roller 108 from guide block 118.

Carrier frame 106 is adapted to be rigidly connected to pipe back-up unit 28 by fasteners such as cap screws 128 to support lugs 130 which project from unit 28 as shown. As shown, four guide rollers 132 are mounted in rectangular formation on carrier frame 106 by means of pins or axles to accommodate a guide bar 134 and maintain the guide bar in vertically movable alignment. Guide bar 134 is adapted to be rigidly connected by means of fasteners such as cap screws 136 to pipe rotating unit 30 as shown.

Vertical movement'of pipe rotating unit 30 relative to pipe back-up unit 28 is maintained within a predetermined limit by means of a dog 138 which is connected to and projects from guide bar 134 into a limit slot 139 defined in carrier frame 106 as shown.

The construction of cradle unit 32 as shown provides parallel alignment and limited vertical movement between rotating unit 30 and back-up unit 28 while permitting adjustable limited radial movement and vertical pivoting of the entire power tong assembly 26. As more fully explained in the referenced US. patent disclosures, the vertical movement between back-up unit 28 and rotating unit 30 is needed to permit longitudinal displacement between a section of pipe being held stationary by back-up unit 28 and a section of pipe being held and rotated by rotating unit 30 as the two sections are being threaded into or out of connection. Means shown in the referenced disclosures may be advantageously utilized to compensate for the weight of rotating unit 30 during its vertical movement with respect to back-up unit 28. The limited radial movement of carrier frame 106 as provided by movement of roller unit 108 within slot 124 permits slight radial movement of power tong assembly 26 with respect to column 10 to compensate for corresponding horizontal deviations of the well pipe within the well bore. Initial radial range adjustment is provided by adjustment of guide block 118 through positioning of adjustment stud 120.

Pivotal movement or rocking of power tong assembly 26 about the axis of roller unit 108 is resiliently limited by a stabilizing unit 140 and 140, as shown in FIGS. 1, 2 and 11. Only unit 140 needs to be described in detail since unit 140' is constructed in mirror image thereof. Unit 140 is shown as a flanged bracket 142 extending inwardly and downwardly from support arm 86 of yoke 24. A bolt 144'extends upwardly through a lug 146 projecting from back-up tong 28 and through a flange 148 projecting from bracket 142 and is secured in position by adjustable lock nuts 150. A pair of resilient coil springs 152 are disposed between the flange 148 and lock nuts 150. The bolt is fitted through lug 146 and flange 148 sufficiently loose to permit the radial movement of tong assembly 26 as previously described. Such construction provides firm yet resilient vertical support of tong assembly 26 against movement about the axis of roller unit 108. Such resilience permits compensation for minor deviations from a vertical position of well pipe extending through tong assembly 26.

As evident from the foregoing description, the power tong and positioning apparatus may have substantial and considerable mass which will require considerable force to pivot the power tong assembly into position over the well bore and away from the well bore as required during performance of well drilling or service operations. Though not shown in FIGS. 1 and 2, the lower support member 14 may be equipped with a gear and pinion arrangement connected to mounting base 40 and driven by a hydraulic motor or the like to pivot the entire structure supported by column 10 as may be desired.

OPERATION OF THE PREFERRED EMBODIMENT In operation, the positioning apparatus is provided with the power tong assembly 26 as shown in FIGS. 1 and 2, positioned over a well bore and secured in position by retaining pin 50. The fluid fitting 102 of cylinder 96 is connected to a hydraulic power system (not shown) which is suitable to inject hydraulic fluid into the cylinder 96 and release the fluid from the cylinder at controlled rates and in controlled volumes to raise and lower tong assembly 26 as desired.

When the pipe is to be disconnected, the pipe is raised or lowered through tong assembly 26 and tion of the pipe joint is within potential grasp of backup unit 28 and free of possible grasp by rotating unit 30. Back-up unit 28 is next actuated to firmly grip the lower section of the pipe joint against rotation and the rotating unit is actuated to grip the upper section of the pipe joint to be rotated. The rotating unit 30 is further actuated to rotate the pipe to unscrew and disconnect the threads of the joint. The operation may then be repeated for the next lower pipe joint to be disconnected in the pipe string.

When the pipe is to be connected the lower pipe joint is positioned and firmly grasped by the back-up unit. Another section of pipe is lowered and centered or stabbed through rotating unit 30 to be threaded into the lower pipe section. The pipe is then rotated by the rotating unit to thread the joint into final connection. Such procedure is repeated for the next section of pipe to be connected.

The foregoing description and drawing will suggest other embodiments and variations to those skilled in the art, all of which are intended to be included in the spirit of the invention as herein set forth.

That being claimed is:

1. Pipe tong positioning apparatus comprising: a vertically disposed support column provided with lower bearing means adapted to be mounted to a fixed support in a well derrick and upper bearing means adapted to be connected to the structure of the derrick to provide vertical and horizontal support for said column I while permitting said column to pivot horizontally; a

vertically movable hollow support collar fitted about said column for pivoting therewith; roller means rigidly mounted on said collar and'mounted in rolling contact with said column for supporting said collar in alignment with said column for movement up and down said column; pipe tong support yoke means rigidly mounted at its first end to said support collar to extend horizontally from said support column; supporting cradle means mounted to the second end of said yoke means, said cradle means being adapted to receive and support a power tong assembly including a pipe back-up unit and a pipe rotating unit disposed in mutually parallel relation; a power source providing linear movement mounted in upright position adjacent to said support column with its lower end mounted to the lower end of said support column; force transfer crosshead means mounted to the upper end of said power source; and flexible force transfer means having one end anchored to said column member and the other end anchored to said yoke means, with an intermediate portion trained across said force transfer crosshead means.

2. The positioning apparatus of claim 1 wherein said support column comprises a central web joined between two parallel flanges, and upper and lower support members respectively mounted to said upper and lower bearing means.

3. The positioning apparatus of claim 2, wherein said support column is rectangularly hollow in configuration and said roller means are mounted within said collar and mounted in rolling contact with the inside faces of said flanges. v I

4. The positioning apparatus of claim 1, wherein said flexible force transfer means includes chain means anchored to the lower end of said support column and to said support yoke means, and said force transfer crosshead means includes chain sprocket means across which said force transfer means are trained.

5. The positioning apparatus of claim 1, wherein said upper and lower bearing means include ball bearing units.

6. The positioning apparatus of claim 3, wherein said roller means comprise a plurality of flanged rollers having roller flanges abutting the sides of said parallel flanges. v

7. The positioning apparatus of claim 1 wherein said power source comprises a piston and cylinder unit having a piston rod connected to said force transfer crosshead means.

8. The positioning apparatus of claim 7 including hydraulic fluid power means for actuating said piston and cylinder unit.

9. The positioning apparatus of claim 7, wherein said flexible force transfer means includes chain means anchored to the lower end of said support column and to said support yoke means, and said force transfer crosshead means includes 'chain sprocket means across which said force transfer means are trained.

10. The positioning apparatus of claim 1, wherein said support column comprises an l-beam.

11. The positioning apparatus of claim 1, wherein said flexible force transfer means includes a pair of parallel chains each anchored to the lower end of said support column and to said support yoke means, and said force transfer crosshead means includes a pair of horizontally spaced chain sprockets across which said chains are respectively trained.

12. Pipe tong positioning apparatus comprising: a vertically disposed support column formed of a central web joined between two parallel flanges and provided with lower and upper support members respectively equipped with a lower bearing unit adapted to be mounted to a fixed support in a well derrick and an upper bearing unit adapted to be connected to the structure of the derrick to provide vertical and horizontal support for said column while permitting said col umn to pivot horizontally; a vertically movable rectangular hollow support collar fitted about said column for pivoting therewith; roller means rigidly mounted within said collar and mounted in rolling contact with the inside faces of said flanges for supporting said collar in alignment with said column for movement up and down said column; pipe tong support yoke means rigidly mounted at its first end to said support collar to extend horizontally from said support column; supporting cradle means mounted to the second end of said yoke means;, said cradle means being adapted to receive and support a power tong assembly including a pipe backup unit and a pipe rotating unit disposed in mutually parallel relation; a power source providing linear movement mounted in upright position adjacent to said support column with its lower end mounted to the lower end of said support column; force transfer crosshead means mounted to the upper end of said power source; and flexible force transfer means having one end anchored to said column member and the other end anchored to said support yoke means, with an intermediate portion trained across said force transfer crosshead means.

13. The positioning apparatus of claim 12, wherein said flexible force transfer means includes a pair of parallel chains each anchored to the lower end of said support column and to said support yoke means, and said force transfer crosshead means includes a pair of horizontally spaced chain sprockets across which said chains are respectively trained. 

1. Pipe tong positioning apparatus comprising: a vertically disposed support column provided with lower bearing means adapted to be mounted to a fixed support in a well derrick and upper bearing means adapted to be connected to the structure of the derrick to provide vertical and horizontal support for said column while permitting said column to pivot horizontally; a vertically movable hollow support collar fitted about said column for pivoting therewith; roller means rigidly mounted on said collar and mounted in rolling contact with said column for supporting said collar in alignment with said column for movement up and down said column; pipe tong support yoke means rigidly mounted at its first end to said support collar to extend horizontally from said support column; supporting cradle means mounted to the second end of said yoke means, said cradle means being adapted to receive and support a power tong assembly including a pipe back-up unit and a pipe rotating unit disposed in mutually parallel relation; a power source providing linear movement mounted in upright position adjacent to said support column with its lower end mounted to the lower end of said support column; force transfer crosshead means mounted to the upper end of said power source; and flexible force transfer means having one end anchored to said column member and the other end anchored to said yoke means, with an intermediate portion trained across said force transfer crosshead means.
 2. The positioning apparatus of claim 1 wherein said support column comprises a central web joined between two parallel flanges, and upper and lower support members respectively mounted to said upper and lower bearing means.
 3. The positioning apparatus of claim 2, wherein said support column is rectangularly hollow in configuration and said roller means are mounted within said collar and mounted in rolling contact with the inside faces of said flanges.
 4. The positioning apparatus of claim 1, wherein said flexible force transfer means includes chain means anchored to the lower end of said support column and to said support yoke means, and said force transfer crosshead means includes chain sprocket means across which said force transfer means are trained.
 5. The positioning apparatus of claim 1, wherein said upper and lower bearing means include ball bearing units.
 6. The positioning apparatus of claim 3, wherein said roller means comprise a plurality of flanged rollers having roller flanges abutting the sides of said parallel flanges.
 7. The positioning apparatus of claim 1 wherein said power source comprises a piston and cylinder unit having a piston rod connected to said force transfer crosshead means.
 8. The positioning apparatus of claim 7 including hydraulic fluid power means for actuating said piston and cylinder unit.
 9. The positioning apparatus of claim 7, wherein said flexible force transfer means includes chain means anchored to the lower end of said support column and to said support yoke means, and said force transfer crosshead means includes chain sprocket means across which said force transfer means are trained.
 10. The positioning apparatus of claim 1, wherein said support column comprises an I-beam.
 11. The positioning apparatus of claim 1, wherein said flexible force transfer means includes a pair of parallel chains each anchored to the lower end of said support column and to said support yoke means, and said force transfer crosshead means includes a pair of horizontally spaced chain sprockets across which said chains are respectively trained.
 12. Pipe tong positioning apparatus comprising: a vertically disposed support column formed of a central web joined between two parallel flanges and provided with lower and upper support members respectively equIpped with a lower bearing unit adapted to be mounted to a fixed support in a well derrick and an upper bearing unit adapted to be connected to the structure of the derrick to provide vertical and horizontal support for said column while permitting said column to pivot horizontally; a vertically movable rectangular hollow support collar fitted about said column for pivoting therewith; roller means rigidly mounted within said collar and mounted in rolling contact with the inside faces of said flanges for supporting said collar in alignment with said column for movement up and down said column; pipe tong support yoke means rigidly mounted at its first end to said support collar to extend horizontally from said support column; supporting cradle means mounted to the second end of said yoke means;, said cradle means being adapted to receive and support a power tong assembly including a pipe back-up unit and a pipe rotating unit disposed in mutually parallel relation; a power source providing linear movement mounted in upright position adjacent to said support column with its lower end mounted to the lower end of said support column; force transfer crosshead means mounted to the upper end of said power source; and flexible force transfer means having one end anchored to said column member and the other end anchored to said support yoke means, with an intermediate portion trained across said force transfer crosshead means.
 13. The positioning apparatus of claim 12, wherein said flexible force transfer means includes a pair of parallel chains each anchored to the lower end of said support column and to said support yoke means, and said force transfer crosshead means includes a pair of horizontally spaced chain sprockets across which said chains are respectively trained. 